JPS6112978B2 - - Google Patents

Abstract

The invention relates to a process for separating seminoble and/or noble metals from an aqueous solution having compounds of these metals dissolved therein by subjecting the solution to reaction with red phosphorus. More particularly, the solution is conveyed through a zone containing a layer of granular red phosphorus particles with a size of 0.01 to 10 mm, which may be used in admixture with active carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating semi-noble metals and/or noble metals from aqueous solutions containing dissolved semi-noble metals and/or noble metal compounds by reaction with red phosphorus.

In this specification, noble metals are gold, silver, mercury, and metals of the platinum group, and semi-noble metals are copper.

Obtaining or recovering mercury, copper, silver, gold and other precious metals from aqueous solutions resulting from industrial processes is necessary for environmental protection reasons in the case of mercury and for economic reasons in the case of other metals. desirable.

To separate mercury from aqueous solutions, it is already possible to separate it by precipitation (DE 3,085,859) or to remove it through an ion exchanger (US 3,085,859) or by liquid-liquid extraction. (Quim.Ind. (Madrid) 1978
24(2), pp. 137 and 139-142) or reduction to metal followed by ejection with hot air (US Pat. No. 4,160,730).

Furthermore, dissolved metal compounds of copper, silver, palladium and mercury can be electrochemically removed from their aqueous solutions using fixed bed and fluidized bed cells (Chem.
(See Ing. Techn. 50 (1978) No. 5, pp. 332-337).

Finally, it is known that when aqueous solutions of salts of mercury, copper, silver, gold, palladium or osmium are treated with red phosphorus, the metals or their phosphides are separated (Gmeline Handbuch der Anorganischen).
Chemie System-Nr.16, Teil B (1964),
(See pages 322-329).

The disadvantages of said methods are that they require a large amount of equipment expenditure or that a preliminary purification of the wastewater to remove contaminant particles is required, or that the degree of separation of metals from the wastewater is insufficient. .

It is therefore an object of the present invention to extract mercury, copper and other metal compounds from an aqueous solution containing dissolved metal compounds such as mercury, copper and precious metals, resulting in virtually metal-incompatible water with low equipment costs and high space-time yields. The objective is to obtain a method for separating metals such as copper and precious metals. This is achieved according to the invention by introducing an aqueous solution containing dissolved compounds of semi-noble metals and/or noble metals into a zone in which granular red phosphorus powder with a particle size of 0.01 to 10 mm is present.

The object of the invention may optionally further have the following characteristics: a) the red phosphorus has a particle size of 0.25 to 1 mm; b) the red phosphorus is chemically activated on its surface; c using a bleaching solution as an activator; d using red phosphorus mixed with activated carbon, with an activated carbon content of up to 98% by weight; e with an activated carbon content of 15-40% by weight; f an aqueous solution. This is followed by a zone with activated carbon, g the activated carbon having a particle size of 0.01 to 10 mm, and h the activated carbon having a particle size of 0.25 to 1 mm.

The method of the invention is suitable for metals with a positive standard potential difference, such as copper, silver, gold, mercury or platinum metals.

The process according to the invention can be carried out continuously using a column arranged vertically and closed at its lower end with a support plate or support fabric, on which the red phosphorus granules rest. I can do it. In this case, it is advisable to improve the supporting function of the plate or fabric by previously applying a layer of fine material, for example sand or activated carbon.

Example 1 (comparative example) In a beaker, red _phosphorus ( ^particle size 250~
500μ) was brought into contact with 250g.

After each 10 minute stirring time, samples were removed from the clear supernatant and their mercury content was analytically determined.
The analysis results are shown in the table below.

Table Reaction time (mm) Mercury content (mg/) 10 4.0 20 3.2 30 2.8 40 1.9 50 1.3 60 1.0 Example 2 (comparative example) Red phosphorus (particle size: 60% is 0.075mm
(smaller) 20g was vigorously stirred in water using a stirrer. A quartz wool filter and Raschig ring were connected after the flask to avoid red phosphorus being carried out. In a flask, add 2/h of mercuric chloride solution with Hg ⁺⁺ 50 mg/h, 5 g/h of NaCl and
11 mg/ml of Cl ₂ were passed in with continuous stirring. The mercury content in the effluent was 0.1-0.5 mg/.

Example 3 (according to the invention) Activated carbon (from Fa. Lurgi) in a column with a diameter of 4 cm
Hydraffin71, particle size: 250-500μ) 25g of powder and 75g of activated carbon and red phosphorus (particle size: 250-500μ) are placed on top of 25g of powder.
A mixture of 250 g of μ) was charged. in this column
Mercury chloride-containing water containing Hg ⁺⁺ 50mg/2/
h was made conductive. The column absorbed a total of 350 g of mercury and the mercury content of the effluent did not increase by more than 0.01 mg/g.

Example 4 (according to the invention) Activated carbon (from Fa. Lurgi) was placed in a column with a diameter of 4 cm.
Add 100g of Hydraffin71 (particle size: 250-500μ) powder, and add 250g of red phosphorus (particle size: 250-500μ) on top of this.
g was laminated. 2/h of an aqueous solution of mercury chloride (Hg ⁺⁺ 50 mg/, sodium chloride (5 g/) and chlorine (11 mg/)) was passed through this column. The column absorbed a total of 608 g of mercury and the mercury content of the effluent did not increase by more than 0.01 mg/.

Example 5 (according to the invention) In a column prepared as in Example 3, Example 4
The same aqueous solution 2/h as in was conducted. The column absorbed a total of 550 g of mercury and the mercury content of the effluent did not increase by more than 0.01 mg/g.

Example 6 (according to the invention) A column prepared as in Example 3 was passed through an aqueous solution 2/h of mercury chloride (Hg ⁺⁺ 50 mg/) and common salt (5 g/). The mercury content after the spill is
It was less than 0.01mg/. The experiment was stopped after the column had absorbed 176 g of mercury without any perceptible flow through.

Example 7 (according to the invention) A column with a diameter of 4 cm was filled with activated carbon (from Fa. Lurgi).
50g of Hydraffin 71 (particle size: 250-500μ) was charged, and 150g of the same activated carbon as above and 500g of red phosphorus (particle size: 250-500μ) were layered thereon. An aqueous solution 2/h containing mercury chloride (Hg ⁺⁺ 50 mg/), common salt (250 g/) and chlorine (11 mg/) was passed through this column. This column is mercury
232 g could be absorbed and the mercury content of the effluent did not increase by more than 0.01 mg/.

Example 8 (according to the invention) The method described in Example 7 was repeated with the exception that the temperature of the column and solution was 45° C. and the mercury concentration of the aqueous solution was Hg ⁺⁺ 10 mg/. In this case, the column was able to absorb 41 g of mercury and the mercury content of the effluent did not increase by more than 0.01 mg/.

Example 9 (According to the Invention) A column similar to that in Example 4 was injected with an aqueous solution of silver sulfate (Ag ⁺ 50 mg/), with a residence time in the column of 15 minutes. Residual silver content in effluent is 0.05
mg/lower. The experiment was stopped after the column had absorbed 27 g of silver without flowing through.

Example 10 (according to the invention) An aqueous silver sulfate solution (Ag ⁺⁺ 50 mg/) was injected into a column similar to that in Example 4, with a residence time of 15
It was a minute. The residual silver content of the effluent was less than 0.05 mg/.

The experiment was stopped after the column had absorbed 20 g of silver without any flow through.

Example 11 (according to the invention) An aqueous copper sulfate solution (Cu ⁺⁺ 50 mg/) was injected into a column similar to that in Example 3, with a residence time in the column of 15 to 30 minutes. The residual copper content of the effluent was approximately 0.2 mg/ml. The column absorbed 129 g of copper without flowing through.

Example 12 (according to the invention) A column with a diameter of 10 cm is charged with a mixture of 750 g of activated carbon and 4000 g of red phosphorus (particle size 3 mm) on a powder of 250 g of activated carbon (Epibon DG from Fa. Lurgi, particle size 3 mm). did. 1/h of an aqueous mercury chloride solution containing 50 mg/h of Hg ⁺⁺ was passed through the column. The column absorbed a total of 200 g of mercury without increasing the mercury content of the effluent by more than 0.01 mg/ml.

Example 13 (according to the invention) A column with a diameter of 4 cm was filled with activated carbon (from Fa. Lurgi).
75 g of activated carbon and red phosphorus (particle size 250-500 μ) on 25 g of powder (hydraffin, particle size 250-500 μ)
250g was charged. Pd ²⁺ 50mg/
1/h of palladium chloride-containing water was passed through the solution. The column absorbed a total of 144 g of palladium and the palladium content of the effluent did not increase beyond 0.1 mg/(analytical detection limit).

Comparing examples 1 and 2 with inventive examples 3 to 8 and 12, the mercury content in the effluent is unexpectedly very low in the inventive examples and in the case of the intermittent process (example 1). The content is less than 1/100, which is less than 1/10 of that in the continuous process using a suspension of red phosphorus (Example 2). Furthermore, Examples 4, 5, 7 and 8 show that the process according to the invention allows an almost quantitative separation of mercury even in the presence of oxidizing agents.

Claims (1)

[Scope of Claims] 1. When semi-noble metals or noble metals are separated from an aqueous solution containing dissolved semi-noble metals or noble metal compounds, the solution is separated into a lower zone having an activated carbon particle layer with a particle size of 0.01 to 10 mm and a particle size of 0.01 to 10 mm. A method for separating semi-precious metals or precious metals from an aqueous solution containing dissolved semi-precious metals or noble metal compounds, characterized by passing the solution through a column divided into multiple zones consisting of an upper zone having a granular red phosphorus layer of 0.01 to 10 mm. . 2. The method of claim 1, wherein the red phosphorus particles have a particle size of 0.25 to 1 mm. 3. The method of claim 1, wherein the red phosphorus particles have a chemically activated surface. 4. The method of claim 3, wherein the red phosphorus is chemically activated using a bleach solution. 5. The method according to claim 1, wherein red phosphorus is used in a mixture with activated carbon, and the activated carbon is used in a proportion of up to 98% by weight. 6. The method according to claim 5, wherein the activated carbon to be mixed is used in a proportion of 15 to 40% by weight. 7. The method according to claim 5, wherein the activated carbon to be mixed consists of particles having a particle size of 0.01 to 10 mm. 8. The method according to claim 5, wherein the activated carbon to be mixed consists of particles having a particle size of 0.25 to 1 mm. 9. The method of claim 1, wherein the activated carbon particles in the layer have a particle size of 0.25 to 1 mm.